全文获取类型
收费全文 | 252篇 |
免费 | 44篇 |
专业分类
林业 | 4篇 |
7篇 | |
综合类 | 2篇 |
农作物 | 10篇 |
水产渔业 | 2篇 |
畜牧兽医 | 268篇 |
植物保护 | 3篇 |
出版年
2023年 | 9篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 24篇 |
2019年 | 1篇 |
2018年 | 8篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 17篇 |
2012年 | 18篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 20篇 |
2008年 | 3篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 7篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1966年 | 1篇 |
1960年 | 2篇 |
1959年 | 1篇 |
1958年 | 4篇 |
1957年 | 2篇 |
排序方式: 共有296条查询结果,搜索用时 15 毫秒
21.
Adriana M. Smith BSc W. Burton Staniar PhD Rebecca K. Splan PhD 《Journal of Equine Veterinary Science》2006,26(5):212-214
Yearling morphometric measurements and variables related to career racing performance were collected on 260 Thoroughbreds to determine correlations between and among these traits. Morphometric measurements were adjusted to 365 days based on interpolation from adjacent age points and included wither and hip height, body length, distal limb length, cannon circumference, heartgirth circumference, and chest width. Measures of career racing ability included total earnings, win percentage, and Standard Starts Index (SSI). Wither height and hip height were favorably correlated with lifetime earnings, SSI, and win percentage. Body length and heartgirth were positively correlated with SSI and win percentage. Leg traits were not correlated with any performance parameters. Horses that had placed in or won a stakes race tended to be taller at the wither and hip as yearlings. Horses categorized as preferring turf tended to be taller at the wither and hip at 365 days than those that preferred to run on dirt. No significant difference in yearling morphometric measurements between sprinters and routers was detected. In addition to phenotype and pedigree information, morphometric measurements taken in the yearling year may allow for more accurate estimation of future performance in the Thoroughbred racehorse. 相似文献
22.
23.
Patti S. Snyder DVM MS Neil G. Shaw DVM Darryl J. Heard BSc BVMS PhD 《Veterinary radiology & ultrasound》1999,40(1):66-72
Two-dimensional echocardiography was performed on Burmese pythons (Python molurus bivittatus) to determine an optimal echocardiographic imaging technique for snakes and to describe the echocardiographic anatomy of the snake heart. Five snakes immobilized with tiletamine/zolazepam and maintained on isoflurane in oxygen were imaged in dorsal recumbency. The portion of the snake's body containing the heart was submerged in warm water to reduce the artifact created by air trapped between and under the scales. Imaging in sagittal planes demonstrated the caudal vena cava, sinus venous valve, right atrium, various portions of the ventricle, horizontal septum, the left aortic arch, and pulmonary artery. Transverse imaging depicted the spatial relationship of the left and right aortic arches and pulmonary artery and the horizontal septum. Basic knowledge of cardiac blood flow in the reptile was necessary to understand the echocardiographic anatomy. 相似文献
24.
Naruepon Kampa DVM Ursula Wennstrom DVM Peter Lord BVSc FRCVS Robert Twardock DVM PhD Enn Maripuu BSc Per Eksell DVM PhD Sten-Olof Fredriksson BSc 《Veterinary radiology & ultrasound》2002,43(4):383-391
Determinations of different methods of measurement of uptake of 99mTc-DTPA using scintigraphy of glomerular filtration rate (GFR) were made from 29 studies on 10 healthy beagle dogs. GFR was measured by calculating the percentage dose uptake (integral method) and rate of uptake (slope method) of 99mTc-DTPA using manual kidney regions of interest (ROI) and automatic kidney and background ROIs at different time periods of the uptake phase. These results were compared using linear regression analysis to the GFR obtained from 99mTc-DTPA plasma clearance using multiple blood samples. The best correlation coefficient between percentage DTPA uptake and GFR by DTPA clearance (r = 0.84, P < 0.001) was derived from time intervals between 30s-120s with a perirenal background ROI at 1 or 2 pixels out from the kidney ROI using automatic kidney ROI at 20% threshold. With the slope method, the best correlation coefficient (r = 0.85, P < 0.001) was obtained from time intervals between 30s-peak with the background ROI at 2 pixels out from the kidney ROI using automatic ROI at 35% threshold. The offset was higher, and the correlation varied more with different ROIs and the method was unreliable at time intervals extending beyond the peak radioactivity. Manual kidney ROIs with automatic background ROIs had slightly lower correlations. With DTPA renography both integral and slope uptake method with automatic kidney and background ROIs are accurate methods to estimate the GFR, but that the integral method is much more stable to variations in ROI size and the duration of the uptake phase of the renogram. 相似文献
25.
Gail I. Anderson BVSc MSc PhD Diplomate ACVS Kent Orlando BSc DDS James P. Waddell MD FRCS 《Veterinary surgery : VS》2001,30(4):311-318
OBJECTIVE: To establish whether hydroxyapatite (HA) coatings applied to metal total-hip-replacement components increased synovitis in the coxofemoral joint of dogs. Study Design-An in vivo research trial and histologic study. ANIMALS: Twenty-three large, mixed-breed dogs. METHODS: Arthroplasty components were implanted with HA on neither stem nor cup, or with HA applied to either the femoral component or with both stem and cup having HA applied in 23 dogs. Synovial inflammation was scored 3, 6, and 12 months after surgery. Synovial membrane thickness; polyethylene particulate load; fibrin exudate; membrane edema; mitotic index; giant-cell, mononuclear histiocyte, lymphocyte, and polymorph number; and collagen degeneration were scored and statistical analyses performed. RESULTS: Operated-side synovial thickness was greatly increased relative to control. Fibrin deposition, intramembranous edema, and collagen degeneration were similar within each time interval among the various component groups. The majority of inflammatory scores among the groups were unchanged. In this 12-month study, the presence of HA coatings appear not to have a marked impact on the development of synovial inflammation. CONCLUSIONS: HA-coated components do appear to contribute somewhat to the inflammatory load within the periprosthetic environment, but this effect is not marked. CLINICAL RELEVANCE: The major advantage of HA addition to arthroplasty components is enhanced osteoconductivity around metallic surfaces. The slight increase in particulate load seen in the presence of HA coatings may contribute to the development of aseptic loosening of arthroplasty components, but is unlikely to be the major causative factor. 相似文献
26.
G. Obolensky Ing. Agr. BSc MSc Dr. Ing. DSc. 《Plant foods for human nutrition (Dordrecht, Netherlands)》1960,7(3):273-288
Summary 1) Some aspects of transplantation of embryo pieces of one species, into the embryo of an other one were discussed, as well as the grafting of an embryo on the endosperm of other varieties, species and even genera (vegetative hyberidization).2) Deep hereditary changes were observed, as well as an incompatibility (negative tropism) to assimilate and to fuse between the embryonic tissues of different species.3) But a positive tropism with a complete assimilation of the tissue can also be observed in all those cases, when the grafted endosperm, belonged to the same species as the one of the transplanted embryo piece.4) This method should be extended in order to produce oil seed crops and particularily soja beans, ripening in northern long day regions (change from short day to long day photoperiodism).5) Ultrasonic vibrations could be usefully applied to improve this grafting method.
Resume 1) Quelques aspects de transplantation d'un fragment d'embryon d'une espèce, dans celui d'une autre, ont été discutés, ainsique le gréffage d'un embryon, sur les réserves nutritives (endosperme) d'autres variétés, espèces et mêmes genres (hybridation végétative).2) Des changements héréditaires profonds ont pu être observés, ainsiqu'une incompatibilité (tropisme négative) de s'assimiler et de fusionner entre les tissus embryonaires de différentes espèces.3) Quand-même un tropisme positif, accompagné d'une assimilation complète des tissues, put être observé dans tous ces cas, ou la réserve nutritive (endosperme) appartenait à la même espèce que le fragment transplanté.4) Cette méthode devrait être approfondie pour pouvoir produire des plantes oléagineuses, en particulier du soja, qui puisse mûrir dans des régions nordiques aux jours longs, pendant la saison de croissance (changement d'un phototropisme de jours courts à celui de jours longs).5) Un traitement aux Ultra-Sons pourrait être avantageusement appliqué afin d'améliorer cette méthode.相似文献
27.
QUALITATIVE AND QUANTITATIVE THYROID IMAGING IN FELINE HYPERTHYROIDISM USING TECHNETIUM-99M AS PERTECHNETATE 总被引:1,自引:0,他引:1
Carmel T. Mooney MVB MPhil Keith L. Thoday BVetMed Phd DVD Jeremy J. Nicoll BSc Phd David L. Doxey BVM&S PhdD 《Veterinary radiology & ultrasound》1992,33(5):313-320
Thyroid imaging using technetium-99m as pertechnetate (99m TcO4 ) was carried out in five healthy, euthyroid and 37 hyperthyroid cats using both pinhole and parallel-hole collimators. Images of greater resolution, necessary to distinguish bilateral lobe involvement, were obtained using the pinhole collimator. Per cent thyriod 99m TcO4 - uptake was calculated in each cat and was significanly (P < 0.001) higher in hyperthyroid compared with euthyroid cats. In the hyperthyroid cats, per cent thyroid uptake was significantly correlated with serum total thyroxine (T4) and triiodothyronine (T3) Concentrations. Per cent thyroid 99m TcO4 - uptake is increased in feline hyperthyrodism and may be calculated using a pinhole collimator alone at the time of qalitative assessment of the extent of thyroid tissue involvement. 相似文献
28.
PAUL W. MORGAN DVM DVSc ALLEN G. BINNINGTON DVM MSc Diplomate ACVS CRAIG W. MILLER DVM MVSc Diplomate ACVS DALE A. SMITH DVM DVSc ANNE VALLIANT BSc JOHN F. PRESCOTT MA Vet MB PhD 《Veterinary surgery : VS》1994,23(6):494-502
This project compared the effects of hydrocolloid (HC) and hydrogel (HG) occlusive dressings and a polyethylene (PE) semi-occlusive dressing on the healing of acute full-thickness skin wounds on the forelimbs of 10 dogs. All treatments resulted in a similar degree of healing at postoperative days 4 and 7. No significant differences existed in the number of wounds that were more than 90% healed at postoperative day 28 between the group treated with the HG dressing and the group treated with the PE dressing. There were significantly fewer wounds more than 90% healed at postoperative day 28 in the group treated with the HC dressing. Wounds under the HG dressing had the largest mean percentage of contraction at postoperative days 21 and 28. Wounds under the HG dressing also had the largest contraction/re-epithelialization ratio (postoperative days 21 and 28) compared with wounds under the PE and HC dressings. Wounds under the PE dressing had a significantly higher mean percentage of re-epithelialization than wounds under both occlusive dressings on postoperative days 14, 21, and 28. Wounds under the two occlusive dressings had exuberant granulation tissue present more often than wounds under the PE dressing. The two occlusive dressings had significantly higher bacterial counts on wounds compared with wounds under the PE dressing; analysis of variance (ANOVA), P = .0008. Wounds under the HC dressing showed the poorest healing in all parameters. 相似文献
29.
LM Antunes MSc DVM JV Roughan BSc PhD & PA Flecknell MA Vet MB PhD DLAS Dip ECVA 《Veterinary anaesthesia and analgesia》2001,28(4):196-203
Objectives To assess a method for monitoring depth of anaesthesia using components of middle latency auditory evoked potential (AEP) waveforms during anaesthesia with fentanyl/fluanisone and midazolam. Study design Prospective observational study. Animals Five female Wistar rats weighing between 210 and 250 g. Methods Implanted electrodes were used to record AEPs in animals receiving five doses of anaesthetic. Recordings were made at 5 minutes post‐injection (deep anaesthesia; no pedal withdrawal response, PWR) and then at 25 minutes (light anaesthesia; strong PWR). Responses showed five characteristic peaks occurring at 11, 14, 23, 42 and 68 ms that were measured for latency of occurrence and peak amplitude. Results Auditory evoked potential peaks P14, N23 and P42 were increased significantly in latency with successive anaesthetic injections [avg. F(1,4) = 12.53, p < 0.001; avg. F(1,4) = 10.6, p < 0.001; avg. F(1,4) = 3.9, p = 0.02, respectively]. Peak N23 showed a significant reduction in latency during the 20 minute recovery period following both the first and second anaesthetic injections (t(3) = 7.52, p = 0.005; t(4) = 5.17, p = 0.007, respectively). Peak P42 occurred significantly earlier 20 minutes following the second anaesthetic injection (t(4) = 4.75, p = 0.009). The mean overall depth of anaesthesia assessed using PWR scores was significantly correlated with the mean latency of peak N23, such that as the strength of PWR increased, N23 occurred significantly earlier (r = ?0.99, p = 0.01). The amplitude difference between peaks N23 and P42 increased after the second and third drug administrations [avg. F(1,4) = 10.65, p = 0.031 and avg. F(1,4) = 11.24, p = 0.028, respectively]. Conclusion The characteristics of these peaks, and in particular latency of peak N23, may provide a useful tool for assessing depth of anaesthesia produced by this, and possibly other anaesthetic agents. 相似文献
30.